The present invention relates to a method for both-side copying wherein the desired number of copies can be made even when copy sheets are jammed while copying the reverse side of a document having images on its both sides.
When copying a plurality of documents on many of the conventional copying machines, a user is required to place a document on a document glass plate one by one for replacement and it is a tough job to keep standing for the replacement of documents especially when the number of documents is large. Recently, therefore, there has been developed and has been put to practical use an automatic document feeding device wherein the plural documents stacked and positioned at a prescribed location can be conveyed one by one automatically onto the document glass plate and copied.
Among documents, incidentally, there are many of so-called both-side documents which have information desired to be copied on both sides thereof and an automatic document feeding device that can be used even for such both-side documents has been developed. In such automatic document feeding device for the both-side document, one side of the document is copied and then the document is turned upside down for copying its reverse side and is delivered, thus the documents are delivered in succession after being copied for both sides. Hereinafter, the first side of the document firstly copied is called as a obverse side and the second side of the document secondly copied is called as a reverse side. When a sheet jamming of a copy sheet (so-called a jam) takes place inside a copy machine while copying the reverse side of the both-side document onto the copy sheet in the copy machine employing aforesaid automatic document feeding device of a document-turnover type capable of reversing the side of document to be copied, it is necessary to clear the jam such as removing the jammed sheet and to continue producing the remaining copies for desired number of copies and then place the document manually on the document glass plate again to make copies corresponding the number of failed copies caused by the jam. This work is very troublesome.
There are some occasions wherein copy sheets are jammed while copying plural both-side documents or copying is desired to be discontinued for some reasons. In such a case, a document is delivered once, and it is no problem to deliver without taking any action when copying the obverse side of the document but it is a problem to deliver the document without taking an action when copying the reverse side of the document because the delivered document may not be in the correct sequence of pages with other documents which have been delivered already and it is necessary to put them in correct sequence, which is troublesome.